Passive radiation optical system module especially for use with light-emitting diodes

ABSTRACT

A passive radiation optical system includes a one-piece module having a plurality of individual optical components wherein the one-piece module is radiation-permeable or reflective. The optical components are connected to one another via predetermined breaking points for forming a radiation optical system module. In addition, the one-piece module can be separated to form optical components that include one or more individual optical components. The one-piece module is particularly for use with light emitting diodes. The passive radiation optical system module is suitable for mass production, and because of its modular principle, it enables flexible adaptation to the shape and size of the desired lighting device, such as lighted advertising or safety lighting.

This is a U.S. National Phase Application under 35 USC 371 ofInternational Application PCT/DE01/02191, filed on Jul. 18, 2000.

FIELD OF THE INVENTION

The present invention relates to a passive radiation optical systemmodule, particularly for use with light-emitting diodes.

BACKGROUND OF THE INVENTION

It is known to use arrays of light-emitting diodes (LEDs), mounted onprinted circuit boards, for lighting purposes. For instance in lightedadvertising, such as backlighted letters, plastic backlighting, and soforth; in safety lighting, such as escape route lighting, orientationlighting, marking lighting systems; and in lighting systems for motorvehicles, it is known, instead of conventional incandescent bulbs or gasdischarge bulbs, to use LEDs, which have a longer service life, betterefficiency in converting electrical energy into radiation energy in thevisible spectral range, and associated with it a lesser power loss and alesser requirement for space. Particularly in lighted advertising, thehigh flexibility in terms of geometrical shaping and the versatility ofcoloring that LEDs offer has great significance.

In German Utility Model DE 298 18 609 U1, an array of circuit boards forarbitrarily setting up LED lighting units is disclosed, in which manycircuit boards are provided that carry light-emitting diodes and thatcohere superficially, are embodied polygonally, and are joined togetherby webs. From this matrix-like array of circuit boards, an arbitrarynumber or partial quantity of the LED-carrying circuit boards can bebroken out, resulting in partial quantities that have versatile designoptions in terms of the geometrical dimensions.

In International Patent Disclosure WO 99/41785, an LED light panel thatcan be preassembled is disclosed. It includes a number of LED chips,onto each of which an optically transparent protective layer is applied.The light panel can be broken apart into subsidiary units.

Normally, light-emitting diodes have an essentially point-shaped lightsource, which has a conical beam with an opening angle of 120° forinstance.

SUMMARY OF THE INVENTION

One object of the present invention is to provide an optical system thatcan be produced in a simple way by mass production and enables flexibleadaptation to given geometric conditions.

According to the invention, the object is attained with a passiveradiation optical system module, in particular for use withlight-emitting diodes, having a plurality of individual passiveradiation optical components,

-   which are radiation-permeable or reflective, and-   which are connected to one another, for forming the passive    radiation optical system module, via connecting means that are    embodied as predetermined breaking points.

An individual radiation optical component is understood to be abeam-forming and/or beam-deflecting optical element, such as focusinglenses, scattering lenses, prisms, or reflectors.

The passive radiation optical system module, hereinafter also called amultiple optical panel, is preferably made in one piece.

The passive radiation optical system module is preferably embodied as acompletely passive optical panel.

Another object of the invention is to provide a multiple optical panelof modular construction, which has many solidly joined-togetherindividual optical components; the multiple optical panel can be brokenapart into optical units that can include a plurality of individualoptical components. As a result, there is great flexibility in terms ofshaping the optical units that can be produced with the multiple opticalpanel, since easy adaptation to given geometric conditions is possible.

Between the individual components, predetermined breaking points areprovided. The predetermined breaking points may be provided along aclosed line, along the circumference of the individual components. As aresult, without using a tool, the user can break the multiple opticalpanel apart, for instance along one edge, into optical units thatinclude one or more individual optical components.

Although the multiple optical panel can be produced by a mass productionmethod, applications for individual items or small-scale production canbe made possible that would otherwise require special development, suchas the production of special injection molds.

The multiple optical panel is especially advantageous in conjunctionwith a multiple array of LED-equipped printed circuit boards, whichlikewise makes subsidiary quantities of solidly joined-together printedcircuit boards possible, with an arbitrarily selectable number oflight-emitting diodes and a virtually arbitrary shaping.

The geometric shaping of the individual components, and in particular ofthe predetermined breaking points, can be adapted to the shaping of theindividual printed circuit boards with LEDs that form the multiplearray.

A modular construction created on the above principle makes a highflexibility of usage possible, since arbitrarily separable optical unitsof various properties, such as color, material, and light focusing orscattering, and so forth, can be combined arbitrarily with multiple LEDpanels that can likewise be broken apart arbitrarily. A plurality ofoptical units of different properties, such as different light exitangles, can advantageously be combined for instance with one multipleLED panel, for instance by being put together.

The multiple optical panel can be produced in a simple way, for instanceby an injection molding process. In applications that have largesurfaces that have to be lighted or backlighted, a plurality of multipleoptical panels can be joined together.

In an advantageous embodiment of the present invention, the multipleoptical panel has individual optical components arranged in atwo-dimensional matrix structure. This kind of multiple optical panel isespecially simple to produce and can be used especially flexibly.

In another advantageous embodiment of the present invention, theindividual components have a square bottom face. Each individualcomponent represents one cell of the matrix structure, which is made upof rows and columns.

In another advantageous embodiment of the present invention, for formingthe predetermined breaking points, zones of reduced material thicknessare provided. If the predetermined breaking points are formed by zonesof reduced material thickness, then the multiple optical panel can havea smooth, uninterrupted surface that is simple to clean. Moreover,injection molds that have zones of reduced material thickness can beproduced simply and with little effort or expense.

In another embodiment of the present invention, the multiple opticalpanel has a smooth surface. As a result, even in optical units thatinclude a plurality of individual optical components, and in which eachindividual optical component is assigned its own light-emitting diode, ahomogeneous light density without a visible transition between theindividual optical components can be attained. This homogeneous lightdensity, or uniform distribution of brightness, is independent of thesize and geometric shaping of the desired application and hence of theoptical unit.

In a further advantageous embodiment of the present invention, forforming the predetermined breaking points, webs between the individualcomponents are provided. Predetermined breaking points formed by websare especially simple to produce and can be easily separated by the usereither by hand or by machine.

In another advantageous embodiment of the present invention, theindividual optical elements each have means for generating a homogeneouslight density on a surface that is visible to the observer when lightradiation strikes it. As a result, for instance, uniformlybrightly-lighted company logos, lighted writing, and so forth can beachieved.

In another advantageous embodiment of the present invention, themultiple optical panel is made entirely of the material known as PMMA(polymethylmethacrylate).

PMMA is widely available, makes easy manipulation in productionpossible, has excellent optical properties, and can be colored in asimple way, which is especially important in lighted advertising andsafety lighting, such as lighting that marks escape routes.Alternatively, the multiple panel can be made entirely of the materialknown as polycarbonate.

In a further advantageous embodiment of the present invention, theindividual optical components have the same geometrical shape as oneanother. This makes a high degree of modularity possible, along withsimple molding, for instance for an injection molding process, as wellas good homogeneity of the light distribution.

The individual optical components and thus the multiple optical panelcan each have reflective, scattering, or focusing optical elements,depending on the application.

The principle involved here avoids the requirement that special LEDoptical elements be developed and produced for individual applications,such as company logos, lighted advertisements, and so forth.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 a, a multiple optical panel with square individual components, ina plan view;

FIG. 1 b, the multiple optical panel of FIG. 1 a in a side view;

FIG. 2, the multiple optical panel of FIG. 1 a, from which an opticalunit including a plurality of individual optical components has been cutout;

FIG. 3 a, a multiple array of LED-equipped printed circuit boards, in aplan view;

FIG. 3 b, the multiple array of FIG. 3 a in a side view;

FIG. 4 a, the multiple array of FIG. 3 a, with an optical unit of FIG.2, in a plan view; and

FIG. 4 b, the multiple array with an optical unit of FIG. 4 a, in a sideview.

DETAILED DESCRIPTION OF THE DRAWINGS

FIG. 1 a shows a multiple optical panel 1 with a plurality of individualoptical components 2 of square bottom face, disposed in a matrixlikestructure. Between the individual optical components 2, predeterminedbreaking points 3 are provided along the edges of the individual opticalcomponents 2. The predetermined breaking points 3 are disposed in twodirections orthogonal to one another. The predetermined breaking points3 are realized by providing that along the predetermined breaking points3, the material thickness of the multiple optical panel 1 is so slightthat it is possible to break the multiple optical panel 1 apart easily,by machine or by hand, into optical units that include one or moreindividual optical components 2. For instance, breaking the multipleoptical panel 1 apart into optical units that include one or moreindividual optical components 2 can be done manually along a fractureedge, without using a tool.

Each individual optical component 2 has an optical element that isassociated with a respective light-emitting diode or laser diode. Theoptical element of an individual optical component 2 converts incidentlight, which is projected conically from a point-shaped light-emittingdiode, into a parallel beam path of homogeneous light density. For thispurpose, a Fresnel lens can for instance be used.

The array of FIG. 1 a has the advantage that the multiple optical panelcan be produced in a simple way by a mass production process, such asinjection molding. Because of the matrixlike construction of themultiple optical panel, with many individual optical components 2disposed in an array, which are identical to one another in theirgeometrical dimensions, a simple, flexible adaptation of the size of thedesired optical array and hence of the optical unit, for an arbitrarynumber of joined individual optical components is possible. Thepredetermined breaking points 3 of reduced material thickness of thePMMA (polymethylmethacrylate) material, because of the attainablehomogeneous light density over a plurality of individual opticalcomponents, in common with suitably designed light-emitting diodes,allow the realization of safety lighting devices, effect lightingsystems, and lighted advertising.

In a departure from the embodiment of FIG. 1, depending on theapplication, the optical element of the individual optical componentscan also be embodied as reflective, scattering, or focusing. If thenumber of individual optical components in one multiple optical panel,or the dimensions of the multiple optical panel, should be inadequatefor the particular application, then a plurality of multiple opticalpanels can for instance be joined together by adhesive bonding, in orderto achieve an arbitrarily large surface.

FIG. 1 b shows a cross section through the multiple optical panel 1 ofFIG. 1 a. The predetermined breaking points 3, with a reduced materialthickness, between the individual optical components 2 are clearlyvisible. The front side 4 of the multiple optical panel, or of theindividual optical components 2, has a smooth surface, so that soiling,for instance in use outdoors, remains slight, and cleaning is easilypossible. The back side 5 of each individual optical component 2 has aninsertion opening for a light-emitting means, such as a light-emittingdiode or a laser diode.

FIG. 2 shows a multiple optical panel 1, from which an optical unit 11that includes eight individual optical components 2 has been separatedalong desired breaking points 3 between the individual opticalcomponents 2. It is understood that the remaining multiple optical panel1* and the optical unit 11 can both be broken apart along furtherpredetermined breaking points 3 to form still other individual opticalcomponents.

FIG. 3 a shows a multiple array 20 of LED-equipped printed circuitboards; the multiple array 20 has a plurality of LED chips 24, which aredisposed with large-area contacts 21 on the printed circuit board 20.Each LED chip 24 has the actual LED light source 23 as well as areflector 22. Once again, this makes for a modular structure oflight-emitting diodes, so that once again arbitrary numbers oflight-emitting diodes that firmly cohere to one another can be created.

FIG. 3 b shows a cross section through the multiple array ofLED-equipped printed circuit boards 20 with LED chips 24 as in FIG. 3 a.The LED chips are shaped such that together with a back side 5 of theindividual optical components 2 that has an insertion opening, a plugconnection can be made.

FIG. 4 a shows the optical unit 11 of FIG. 2, mounted on the multiplearray of LED-equipped printed circuit boards 20. It can be seen that thecenter points of the individual optical components 2 of the optical unit11 are each disposed such that they match the LED light sources 23. Thuseach individual optical component 2 is associated with one LED chip 24.

FIG. 4 b shows a cross section through the connection of the opticalunit 11 and multiple array of LED-equipped printed circuit boards 20 ofFIG. 4 a. The individual optical components 2 are each mounted by theirback side 5 on the LED chip 24 of the multiple array of LED-equippedprinted circuit boards 20. It can be seen that the individual opticalcomponents 2 and the overall optical unit 11 have a flat, smoothsurface.

Besides the square shape, described, of the individual opticalcomponents 2, these components can also have other shapes, such ashexagonal, triangular, rectangular, and so forth.

1. A passive optical one-piece module for use with light-emittingdiodes, said passive optical one-piece module consisting of ahomogeneous material and comprising: a plurality of individual passiveoptical components, which are radiation-permeable or reflective, andpredetermined breaking points arranged in said passive optical one-piecemodule.
 2. The passive optical one-piece module of claim 1, wherein saidplurality of individual passive optical components are arranged in atwo-dimensional matrix structure.
 3. The passive optical one-piecemodule of claim 2, wherein each of said individual passive opticalcomponents has a square bottom face and forms one cell of saidtwo-dimensional matrix structure, said cell being defined by rows andcolumns of said two-dimensional matrix structure.
 4. The passive opticalone-piece module of claim 1, wherein zones of reduced material thicknessare provided for forming said predetermined breaking points.
 5. Thepassive optical one-piece module of claim 1, wherein webs between atleast two optical components of said individual passive opticalcomponents form said predetermined breaking points.
 6. The passiveoptical one-piece module claim 1, wherein said passive optical one-piecemodule has a smooth surface.
 7. The passive optical one-piece module ofclaim 6, wherein individual optical components of said individualpassive optical components have means for generating a homogeneous lightdensity at said smooth surface in the event of incident radiation. 8.The passive optical one-piece module of claim 1, wherein saidhomogeneous material of said passive optical module comprises PMMA. 9.The passive optical one-piece module of claim 1, wherein each of saidindividual passive optical elements has an identical geometric shape.10. The passive optical one-piece module of claim 1, wherein each ofsaid individual passive optical components has a back side with aplug-in opening for receiving a light-emitting diode.
 11. The passiveoptical one-piece module of claim 1, wherein each optical component ofsaid plurality of individual passive optical components is connected tothe others of said plurality of individual passive optical components byat least one of said breaking points.
 12. The passive optical one-piecemodule of claim 1, wherein said predetermined breaking points are formedby said homogeneous material of said individual passive opticalcomponents.
 13. A passive optical one-piece module, comprising: aplurality of individual passive optical components, each of said opticalcomponents being radiation permeable or reflective; and breaking pointsarranged in said optical module, wherein the breaking points arearranged in material of said passive optical components.
 14. The passiveoptical one-piece module of claim 13, wherein each optical component ofsaid plurality of individual passive optical components is connected tothe others of said plurality of individual passive optical components byat least one of said breaking points.
 15. The passive optical one-piecemodule of claim 13, wherein each of said breaking points is formed frommaterial of two adjacent ones of said plurality of individual passiveoptical components.